Brake system for rail cars

ABSTRACT

A brake system for rail cars is disclosed. The brake system includes a first source for providing a braking force to a first and a second braking apparatus, a second source for providing a separate force to the first and a second braking apparatus, and a manifold for simultaneously delivering a braking force from either the first source or the second source to the first and second braking apparatus. The manifold includes a positionable valve operable under the influence of pressure differentials applied thereto by the first source and the second source and wherein the position of the valve controls which braking force will be applied to the first and second braking apparatus. The brake system further includes a controller arranged in operable combination with the first source and the second source for inhibiting a braking force from the second source being directed to the first and the second force to the first and the second braking apparatus.

This application is a continuation of application Ser. No. 09/345,022,filed Jul. 2, 1999.

FIELD OF THE INVENTION

A brake system for rail cars comprising an intensifier, a spool valve, apump, and at least two hydraulic or air cylinders.

BACKGROUND OF THE INVENTION

The rail network in North America is the largest in the world, operatingwith the high axle loads customarily used with heavy freight haulingrailways. For many years there has been a trend in North America to useheavier and heavier freight cars. This trend has required designers ofbrake systems to attempt to pack more and more brake performance into asmaller and smaller space.

In a paper presented at the September, 1971 Annual Meeting of the AirBrake Association (1971). Thomas H. Engle, Senior Project Engineer ofthe New York Air Brake Company (of Starbuck Avenue, Watertown, N.Y.)disclosed that “About four years ago, our Company decided that in thelong run the best solution for this squeeze would be a hydro-pneumaticbraking system which included both hand and power braking, and whichwould use a mechanical lock on the handbrake so as to hold a car, onwhich handbrakes had been applied, even in the absence of hydraulicpressure.”

In 1972, U.S. Pat. No. 3,707,309 was issued to Mr. Engle. This patentclaimed a fluid operated brake system for a railway car which compriseda hydraulic hand brake control unit which had to be manually activatedand deactivated. Failure to deactivate the control unit at theappropriate time causes the brakes to maintain contact with the wheels,thus increasing wear and tear upon the system and leading to prematurefailure.

By no later Mar. 16, 1976, when U.S. Pat. No. 3,944,286 issued to ThomasH. Engle, there existed, according to such patent, “ . . . railwayregulations which require a crewman to move or confirm all parkingbrakes to an ‘OFF’ position . . . ” The patent disclosed that “The priorart systems . . . may create problems in use since it is frequently thecase that the parking brake has not been fully unlocked and released bya crewman before an attempt is made to move the car. Obviously, this cancause numerous delays to locate the stuck brakes, undue brake wear ifsome movement does occur and similar deleterious effects.” The solutionto this problem presented in this patent was to provide a brake systemwhich first required a crewman to release the parking brake of aparticular car. The patentees disclosed that “If, however, the crewmanhas failed to even partially release the parking brake of a particularcar, the booster 70 will be ineffective to release either the brake orthe brake locking mechanism.”

Some twenty-three years later, when Thomas H. Engles's U.S. Pat. No.5,746,293 issued in May of 1998, the problems discussed in his earlierpatent had not been solved. Thus, as is disclosed at lines 50-55 ofcolumn 1 of this 1998 Engle patent, “ . . . these hand brakes have beena source of problems. This is particularly the case when such handbrakes are not released when a train consist is ready to move over thetracks . . . ”

About the same time that U.S. Pat. No. 5,746,293 issued to Mr. Engle,U.S. Pat. No. 5,767,973 issued to Hans J. Naumann. This latter patentdisclosed that “ . . . the rail network in the North America is . . .characterized by an inordinately high number of railroad accidents andderailments; these incidents occur at a substantially higher rate inNorth America than anywhere else in the world.”

Applicant believes that one of the causes of this problem is a failureto properly operate and maintain the braking systems on rail cars. Suchlack of proper operation and maintenance is often due to the complexityof such systems, difficulty of access to the components in such systems,and the lack of readily apparent visual indicators warning of systemstatus.

It is an object of this invention to provide a brake system which ismore reliable than prior art brake systems.

It is another object of this invention to provide a brake system whichallows ready visual access to determine whether the brakes aredisengaged.

It is yet another object of this invention to provide a brake systemwhich can readily be attached to conventional railway trucks.

It is yet another object of this invention to provide a brake systemwhich can readily be removed from conventional railway trucks forservice.

It is yet another object of this invention to provide a brake systemwhich automatically disengages a hand brake upon application of atrain's service brake.

It is yet another object of this invention to provide a brake systemwhich is relatively lightweight, small, and inexpensive.

It is yet another object of this invention to provide a brake systemwhich can be used with a railway truck and a railway car.

It is yet another object of this invention to provide a brake systemwhich will require substantially less maintenance than prior art brakingsystems, less time to do such maintenance, and less expense to do suchmaintenance.

SUMMARY OF THE INVENTION

In accordance this invention, there is provided a brake system for railcars comprised of an intensifier, a spool valve connected to saidintensifier, a pump connected to said spool valve, a first cylinderconnected to said spool valve, and a second cylinder connected to saidspool valve.

BRIEF DESCRIPTION OF THE DRAWINGS

The claimed invention will be described by reference to thespecification and to the following drawings, in which like numeralsrefer to like elements, and in which:

FIG. 1 is a schematic view of one preferred brake apparatus of theinvention mounted on a railway truck,

FIG. 2 is a schematic view of the brake apparatus of FIG. 1, showing theposition of its components vis-a-vis the railway truck,

FIG. 2A is a schematic of a hydraulic circuit involving a spool valve ofthe brake apparatus,

FIG. 3 is a partial side view of the brake apparatus of FIG. 2,

FIG. 4 is a schematic view of a pin block which may be used inconjunction with the apparatus of FIG. 1;

FIG. 5 is a perspective view of a brake lever and clevis which may beused in conjunction with the pin block of FIG. 4, and

FIG. 6 is a perspective view of a brake head.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of a railway truck 10 onto which, in thepreferred embodiment depicted, a brake system is mounted. In theembodiment depicted, the brake system is comprised of hydraulic fluidreservoir 13, air master cylinder 14, fluid master cylinder 16, spoolvalve 17, first hydraulic cylinder 18, second hydraulic cylinder 20,hand pump 22, brake head 24, brake lever 26, and pin block 28.

As will be appreciated by those skilled in the art, the hand pump 22 isbut one preferred independent means of providing a separate source ofbrake force, commonly used for parking cars when no air pressure isavailable at cylinder 14. One may use other means, manually and/orautomatically operated, for applying force to the brakes. It ispreferred, in general, that these other means include an air orhydraulic cylinder powered by one or more suitable activation means,which may be manual or automatic.

In one embodiment, not shown, the hand pump 22 is replaced with an airor hydraulic cylinder powered by an alternate or remotely applied force.Thus, by way of illustration, a series of railroad cars make have amultiplicity of brake systems, each with a pump 22 centrally operatedand controlled from one location.

In the embodiment depicted in FIG. 1, the brake system is mounted onto arailway truck 10. As is known to those skilled in the art, a railwaytruck supports one end of a rail car and generally is comprised ofbolster 30, side frame 32, side frame 34, wheel assembly 36, wheelassembly 38, and suspension springs 40. Railway trucks and theirassociated braking systems are well known to those skilled in the artand are described, e.g., in U.S. Pat. Nos. 5,040,466, 4,981,082,4,907,514, 4,844,554, 4,838,174, 4,766,818, 4,679,506, 4,669,391,4,630,715, 4,428,301, and the like. The disclosure of each of theseUnited States patents is hereby incorporated by reference into thisspecification.

In another embodiment, not shown, the reservoir 13, the intensifier(comprised of elements 14 and 16), the spool valve 17, and the pump 22can be mounted on the associated railway car and hydraulically connectedto the remaining components on the railway truck 10. In yet anotherembodiment, the reservoir 13 can be mounted on bolster 13. As willapparent to those skilled in the art, it does not matter where thesecomponents are located as long as they are operatively connected to eachother.

FIG. 2 also is a perspective view of railway truck 10 onto which thecomponents of the preferred brake system 12 are mounted. Referring toFIG. 2, air from an air reservoir (not shown) is fed to air mastercylinder 14 and hydraulic master cylinder 16, which collectively act asan intensifier. In general, an air line (not shown) is connected fromone railway car to another; whenever the pressure in such air line dropsbelow a predetermined value, air is fed from an air reservoir (notshown) to the line 42 to provide the desired air pressure to the system.

Under stable conditions, a constant pressure is applied via line 42 toelements 14 and 16. When the brakes 44, 46, 48, and 50 are off, the airpressure in line 42 is atmospheric pressure, generally about 14.7 poundsper square inch. When the brakes 44, 46, 48, and 50 are to be applied, aswitch (not shown) is activated which reduces the pressure in the airline connecting the railway cars. The reduced pressure state causes theair reservoir (not shown) to feed air into line 42, thereby increasingthe pressure in such line to a predetermined value, depending upon thesize of the railway truck, often from about 40 to about 70 pounds persquare inch.

In the preferred embodiment depicted, air master cylinder 14 andhydraulic master cylinder 16 collectively act as an intensifier, whosefunction is to convert the increased air pressure within line 42 tohydraulic pressure; many such intensifiers comprise only one integralelement. These intensifier units are often referred to as “boosters” or“air powered hydraulic pumps” or “air powered hydraulic systems” or “airpowered hydraulic intensifiers.” They are well known in the art and aredescribed, e.g., in U.S. Pat. Nos. 5,782,158, 5,772,289, 5,724,852,5,634,778, 5,375,814, 5,303,643, 5,290,140, 5,271,881, 5,242,358,4,993,226, 4,784,579, 4,773,222, 4,582,278, 4,011,724, and the like. Thedisclosure of each of these United States patents is hereby incorporatedby reference into this specification.

One such intensifier, which is referred to as a pneumatic/hydraulicpressure intensifier, is disclosed in U.S. Pat. No. 5,746,293, theentire disclosure of which is hereby incorporated by reference into thisspecification.

It is preferred that the intensifier, which comprises air cylinder 14and hydraulic cylinder 16, be capable of converting from about 50 toabout 75 pounds per square inch of air pressure into an output hydraulicpressure of from about 500 to about 2,000 pounds per square inch. Theratio of the hydraulic pressure produced by the intensifier to the inputair pressure should preferably be from about 5/1 to about 25/1 and, inone embodiment, is from about 8/1 to 17/1.

For the sake of simplicity of representation, applicant has depicted theintensifier used in his device as being comprised of two separate units,air cylinder 14 and hydraulic cylinder 16. As is well known to thoseskilled in the art, the commercially available intensifier units areoften sold as one integral package whose elements provide severaldifferent functions. These commercially available intensifiers, as longas they provide the degree of pressure amplification required, may beused in the device of this invention.

In one embodiment, hydraulic cylinder 16 is an air cylinder.

Referring again to FIG. 2, the hydraulic fluid under amplified pressureis fed via line 52 to spool valve 17. As is known to those skilled inthe art, a spool valve is a slide-type hydraulic valve in which themovable part is a “spool.” These valves, and their use in brake systems,are well known and are described, e.g., in U.S. Pat. Nos. 5,882,089,5,836,845, 5,711,584, 5,624,164, 5,547,264, 5,442,916, 5,417,480,5,328,002, 5,323,688, 5,188,002, 5,141,293, 5,123,712, and the like. Thedisclosure of each of these United States patents is hereby incorporatedby reference into this specification.

Hydraulic logic circuits for controlling spool valves, and theiroutputs, are well known. One such logic circuit is disclosed in U.S.Pat. No. 4,201,277 of Bruno Meier et al. In this patent, hydraulicactivators are provided with a relief valve which serves to permitcommunication between a disengaging cylinder chamber and a work cylinderchamber. The open position of the relief valve occurs when the releaseapparatus for the rotatable friction brake member is closed. The closedposition of the relief valve occurs after the rotating brake isreleased. The entire disclosure of this patent is hereby incorporated byreference into this specification.

Other hydraulic logic circuits for controlling spool valves aredisclosed, e.g., in U.S. Pat. Nos. 5,218,997, 4,811,650, 4,812,789,4,154,261, and the like. The disclosure of each of these United Statespatents is hereby incorporated by reference into this specification.Furthermore, the spool valves can be replaced, in part or whole, byother hydraulic control valves performing the same function.

Referring again to FIG. 2, it will be seen that spool valve 17 ishydraulically conneced to both hydraulic cylinder 16 (via line 52), andto hand pump 22 (via line 54).

Spool valve 17 has outputs 56, 58, 60, and 62. For the sake ofsimplicity of representation, the circuit logic involving spool valve 17is schematically illustrated in FIG. 2A.

Referring to FIG. 2A, it will be seen that spool valve 17 is capable offeeding hydraulic fluid via lines 56 and 58 to hydraulic cylinders 18and 20, respectively. Such fluid flow will cause these hydrauliccylinders to move in a manner such that they will activate the brakes,as will be discussed in more detail later in this specification.

The fluid flow through lines 56 and 58 can be caused by means of fluidfrom hydraulic cylinder 16, which is caused to flow because of airpressure in air cylinder 14. As is discussed elsewhere in thisspecification, this fluid flow occurs when the service brake is appliedby the engineer; and it flows through both of lines 56 and 58 tocylinders 18 and 20.

The activation of hand pump 22 will also cause fluid flow through lines56 and 58 and the resultant movement of cylinders 18 and 20.

When the pressure applied by the hand pump 22 is equal to the pressureapplied through line 52, then the spool within spool valve 17 will notmove, and no fluid will flow to either cylinder 18 or cylinder 20.

If no service brake is applied by the engineer, then no fluid will flowthrough line 52. In that case, fluid flowing though line 54 because ofthe use of hand pump 22 will cause the spool to move within valve 17 andthe resultant movement of cylinders 18 and 20.

If, however, the service brake is applied by he engineer, the system isdesigned in such a manner that the pressure exerted through line 52 uponthe spool will always be greater than the pressure exerted upon thespool through line 54. Thus, when the service brake is applied and thehand brake is not applied, such pressure will cause the movement ofcylinders 18 and 20. When both the service brake is applied and the handbrake is applied cylinders 18 and 20 will still move because of thegreater pressure from line 52. Furthermore, a pressure sensor operablydisposed within line 52 at point 60 will sense the increased thepressure in such line and cause a pressure controller 62 to operablyopen a valve in line 64 located schematically at point 64 and to releasepressure back into pump 22.

The schematic of FIG. 2A provides one means for releasing the pressurein line 54 when the pressure in line 52 exceeds a certain specifiedvalue. It is only one of many possible means of achieving this end, allof which are within the scope of this invention.

In the preferred embodiment depicted in FIG. 2A, an isolation valve 66is disposed within line 58, and an isolation valve 68 is disposed withinline 56.

When the pressure at point 60 exceeds a certain specified orpredetermined value or level, then isolation valves 66 and 68 allow highpressure fluid to flow back into the system. However, until and unlessthe pressure art point 60 exceeds such a predetermined or specifiedvalue or level, the system will only allow forward flow in lines 56 and58 unless and until the pressure in the cylinders 18 and 20 is manuallyreleased back into the system by means of a release valve (not shown).When such forward flow has achieved the objective of moving thecylinders 18 and 20 the desired extent, isolation valves 66 and 68 willclose and not allow flow in either direction until and unless it sensesthe pressure in line 52 has exceeded the aforementioned specified level.

Referring again to FIG. 2, it will be seen that the hydraulic cylinders18 and 20 are disposed above the bolster 30, thus being removed to somedegree from the risk of contact with moving debris from the wheels ofthe truck. As will be apparent to those skilled in the art, the bolster30 moves up and down on springs 40. The hydraulic cylinders 18 and 20are sufficiently spaced that, even at the maximum height of bolster 30,it will not contact either of such cylinders. In general, when the truck10 is motionless, the hydraulic cylinders 18 and 20 are at least about 2inches above the bolster 30 when the truck is unloaded.

Referring again to FIG. 2, attachment pins 70, 72, 74, and 76 areadapted to engage the slack adjusters 78, 80, 82, and 84. These slackadjusters are shown in greater detail in FIG. 3.

FIG. 3 is a side view of the side frame 32 (see FIG. 2). It will beappreciated the side frame on the other side of the truck, side frame34, will have a similar configuration.

Referring to FIG. 3, it will be seen that cylinder 18 is connected tolever arm 26 at point 86. The structure of lever arm 26 is shown ingreater detail in FIG. 5.

Returning to FIG. 5, a clevis 90, attached to cylinder 18 and equippedwith orifices 92 and 94, is aligned with orifice 96 defined by lever arm26 and is removably attached thereto by means of a pin 98 (see FIG. 3).Lever arm 26 furthermore defines an orifice 100, preferably having arectangular margin, and which is adapted to receive a rectangularprotrusion 102 of brake head 24 (see FIG. 6). The rectangular protrusion102 on brake head 24 defines an orifice 104 adapted to be aligned withthe orifices 106 and 108 of lever arm 26 (see FIG. 5); and, when soaligned, the lever arm 26 may be removably attached to the brake head 24by means of a pin.

Referring again to FIG. 5, lever arm 26 further defines an orifice 110which is adapted to receive rod 112 of pin block 28.

The connection of lever arm 26 to the hydraulic cylinder 18, the brakehead 24, and the pin block 28 is similar to the connection of lever arm27, the free rod end of hydraulic cylinder 18, the brake head 25, andthe pin block 29.

As will be apparent to those skilled in the art, these connections allowbrake heads 24 and 25 to self align to the wheels 37, 39, 41, and 43(see FIG. 2). This phenomenon allows brake pads 44 and 46 to rotate intopositions wherein they are in full contact with the wheels.

It will be apparent that many other designs may be used that willaccomplish the same function. Furthermore, spring force or other means(not shown) can be introduced at the various connection points toaccommodate tolerances and to balance forces or moments to maintain theshoe 46 in proper relation to the wheel 37.

Referring again to FIG. 3, it will be seen that slack adjusters 78 and80 are connected to hydraulic cylinder 18, one for limiting movement inone direction, the other for limiting movement in the other direction.These slack adjusters are well known in the railway art and aredescribed, e.g., in U.S. Pat. Nos. 5,813,771, 5,615,755, 5,476,269,5,465,816, 5,253,736, 5,246,081, 5,197,373, 5,067,872, 4,973,206,4,683,991, 4,676,346, 4,662,485, 4,646,882, 4,530,422, 4,498,711,4,497,392, 4,457,407, 4,420,066, and the like. The entire description ofeach of these United States patents is hereby incorporated by referenceinto this specification.

Furthermore, in the preferred embodiments depicted, the levers, slackadjusters, and cylinders are supported by and forces reacted into theside frames. An alternative means could have these elements supported bythe bolster and/or by another structure.

It is to be understood that the aforementioned description isillustrative only and that changes can be made in the apparatus, in theingredients and their proportions, and in the sequence of combinationsand process steps, as well as in other aspects of the inventiondiscussed herein, without departing from the scope of the invention asdefined in the following claims.

In one embodiment, the air powered fluid system, instead of producing ahydraulic flow at an increased pressure in response to an air flow at alesser pressure, produces a fluid flow at an increased pressure inresponse to the an air flow at a lesser pressure. The term fluid, asused in this specification, is intended to encompass both air and liquidmaterial.

The spool valve referred to in this specification acts as a manifold,directing fluid flow to certain locations in response to certainconditions. Other manifolds may also be used, and other valves thanspool valves may also be used.

The hydraulic cylinders referred to in this specification are but onemeans of providing linear movement in response to the flow of fluidunder pressure. Other devices, such as other movable cylinders, also maybe used.

I claim:
 1. A brake system for rail cars, comprising: (a) an air poweredfluid system with an inlet port and an outlet port, wherein said airpowered system produces a first flow or fluid under pressure at saidoutlet port in response to a predetermined pressurized air flow beingsupplied to said inlet port; (b) an apparatus for producing a secondflow of fluid under pressure; (c) a manifold including a valve whoseposition is controlled by fluid pressure differentials applied theretoby the first and the second flow of fluids under pressure, and whereinsaid manifold is connected to and simultaneously delivers said firstflow of fluid under pressure from said outlet port to each of a firstbraking apparatus arranged in operable combination with a first set ofwheels disposed to one side of a rail car and including a first movabledriver, and a second braking apparatus arranged in operable combinationwith a second set of wheels disposed to an opposite side of said railcar and including a second movable driver, and wherein:
 1. when saidfirst flow of fluid under pressure is at a first specified level ofpressure, said manifold valve is positioned such that said first flow offluid under pressure from the outlet of said air powered system issimultaneously delivered to said first and said second movable driversof said first and said second braking apparatus, respectively; and 2.when said first flow of fluid under pressure is at a specified level ofpressure lower than said first specified level of pressure, saidmanifold valve is positioned such that said second flow of fluid underpressure from said apparatus is simultaneously delivered to said firstand said second movable drivers of said first and said. second brakingapparatus, respectively; and (d) a controller arranged in operablecombination with said air powered fluid system and said apparatus forinhibiting said manifold valve from being positioned by the second flowof fluid under pressure from said apparatus when an air flow having apredetermined pressure is supplied to the inlet port of said air poweredsystem.
 2. The brake system as recited in claim 1, wherein said firstmovable driver is arranged in operable combination with a firstisolation valve.
 3. The brake system as recited in claim 1, wherein saidsecond movable driver is arranged in operable combination with a secondisolation valve.
 4. The brake system as recited in claim 1, wherein: (a)said first braking apparatus is comprised of a first slack adjuster anda second slack adjuster attached to said first movable driver, (b) saidsecond braking apparatus is comprised of a third slack adjuster and afourth slack adjuster attached to said second movable driver, and (c)said first flow of fluid is a first flow of hydraulic fluid.
 5. Thebrake system as recited in claim 4, wherein each of said first slackadjuster, said second slack adjuster, said third slack adjuster, andsaid fourth slack adjuster includes a connector for connecting arespective slack adjuster to a railway truck.
 6. A brake system forrailcars as recited in claim 1, wherein said apparatus for producing aflow of fluid under pressure is a hand pump.
 7. The brake system asrecited in claim 6, wherein said apparatus operable independent of saidintensifier for producing a second flow of pressurized fluid is a handpump.
 8. A brake system for rail cars, comprising: a first source forproviding a pressurized fluid braking force to each of a first and asecond braking apparatus; a second source for providing a separatepressurized fluid braking force to each of said first and said secondbraking apparatus; a manifold for simultaneously directing to said firstbraking apparatus and said second braking apparatus said braking forcefrom either said first source or said second source, said manifoldincluding a positionable valve operable under the influence of pressuredifferentials applied thereto by said first source and said secondsource, and wherein the position of said valve controls which brakingforce is delivered to said first braking apparatus and said secondbraking apparatus; and a controller arranged in operable combinationwith said first source and said second source for inhibiting the brakingforce from said second source from being directed to said first brakingapparatus and said second braking apparatus when both said first sourceand said second source are concomitantly enabled to apply a brakingforce to said first braking apparatus and said second braking apparatus.